Fluid pressure operated device



Jan. 2, 1934. 1. G. RINGSQI'ROM 1,

FLUID PRESSURE OPERATED DEVICE Filed July 8, 1929 Patented Jan. 2, 1934 FLUID PRESSURE OPERATED DEVICE Ivan G. Ringstrom, St. Paul, Minn. Application July 8, 1929. Serial No. 376,567

'5 Claims.

My invention relates to fluid pressure operated devices, and particularly to devices for controlling and indicating the fluid pressure in receptacles indicating and controlling apparatus.

An object of the invention resides in providing a member for varying in positions of elevation in accordance with changes in fluid pressure, and

in connecting therewith a conduit communicating with said reservoir. 7

Another object of the invention resides in providing control'means operated by said member for controllng the fiuid pressure of the fluid within said reservoir and in further providing means i operable in conjunction therewith capable of adjustment for friction loss of the fluid within said conduit.

A still further object of the invention resides in employing a pair of superimposed receptacles,

'the lower of said receptacles having a quantity of mercury therein, and in providing means having a passageway extending into said mercury and communicating with said upper receptacle.

Another object of the invention resides in connecting said lower chamber with said conduit from said reservoir to bring said lower chamber under the fluid pressure of said reservoir.

Another object of the invention resides in providing a cap capping said passageway and having an orifice therein wholly submerged within said mercury for dampening the action of said member.

A feature of the invention resides in providing in said upper chamber'a float adapted to be raised and lowered upon changes of the elevation of the mercury within said upper chamber.

An object of the invention resides in providing a mercury switch adapted to be operated by said float, said mercury switch including a pivoted tube having contacts therein adapted to be immersed within the mercury to form a connection therebetween. I

Another object of the invention resides in attaching an arm to said switch adapted to be operated by said float for swinging said tube to open and close said switch. l

A feature of the invention resides in employing an inverted pendulum attached to said switch and normally off center, and adapted to pass center and to assume an oppositely disposed oif center position upon partial movement of said arm and float.

Another object of the invention resides in form-'- ing said tube with a bend intermediate the ends thereof for preventing the switch from opening or reservoirs remotely disposed from the or closing while said inverted pendulum is over dead center. i

A feature of the invention resides in providing said float with stops adapted. to engage said arm, said stops being independently adjustable for controlling the fluid pressure within said reservoir,,and to compensate for friction losses within said conduit.

.Other objects of the invention reside in the details of construction thereof, and in the novel combination and arrangement of parts hereinafter illustrated or described.

In the drawing:

Fig. 1 is a diagrammatic elevational sectional view illustrating an embodiment of my invention.

Fig. 2 is an enlarged longitudinal sectional view of the cap having the submerged orifice.

In the control of fluid pressure or stator head, as in the case of water reservoirs, it is desired to control the changes of pressure or head occasioned normally at the source of pressure. Such changes I in pressure are frequently accompanied by surges in pressure brought about by starting or stopping of pumps or opening or closing of valves, which surges do not affect the true pressure or head at the source. The ordinary types of control apparatus, such as the Bourdon tube, bellows or diaphragm type readily respond to 'such surges, thereby causing undesirable operation of the pumps or other sources of fluid pressure. At the same time, such devices are short lived, relatively inaccurate-and more or less undependable. My invention overcomes these difiiculties by providing a device which is extremely positive inaction, is practically fool proof and is at all times accurate and reliable.

My invention, as will presently become apparent, is applicable to the indicating and controlling of variations in fluid pressure within any type of receptacle, reservoir, boiler or other similar container, though the same is particularly advantageous in use in controlling the height of water in water reservoirs, standpipes and the like. For this reason, the invention has been described as applying to a water reservoir and isused for indicating and controlling the level of the water within the reservoir.

The device consists primarily of two structures; a member indicated in its entiretyat A, varying in positions of elevation in accordance with changes in fluid pressure, and an electric switch B adapted to be operated thereby. These devices will now be described in detail.

The member A consists of two superimposed receptacles 10 and 11 connected together by means of a tube or conduit 12, or any other device having a suitable passageway therein. Both of these receptacles are preferably round in formation, though other shapes may be employed. The receptacle 10 is provided with a bottom 13 integrally connected thereto and to which the tube 12 is similarly attached. This receptacle is open at the top and adapted to be closed by a removable cover 14 which is formed with a flange 15 adapted to hold the same properly centered upon the said receptacle. The receptacle 11 is similarly constructed to the receptacle 10 and is provided with a bottom 16 and a top 17, both integrally connected thereto. The upper portion of the top 17 is threaded to receive a T 18, one branch 19 of which is screwed into said top and the opposite branch 20 of which extends up wardly from the said receptacle to receive a bushing 21 through which the tube 12 extends. The other branch 22 of the T 18 is threaded to receive a pipe 23 which is directly coupled through the distributing lines of the water system connected with the water reservoir. A pet cook 70 may be connected to a T 24 inserted in this line for per mitting of the escape of air trapped within the system. If desired, a suitable valve may also be inserted in the line for shutting off the supply of water to the device.

The tube or conduit 12, as shown in Fig. 1, extends into the lower portion of the receptacle 11, which is partially filled with mercury, as indicated at 25. This tube is provided at the end thereof with a cap 26 which is shown in detail in Fig. 2. This cap is internally threaded at 27 to screw upon the threaded end of the tube 12 and is formed with a passageway 28 extending partially through the lower end of the said cap. At the extreme end of this cap is formed an orifice 29 which communicates with passageway 28 and with the interior of the receptacle 11.

Throughout the entire operation of the device, the orifice 29 is immersed within the mercury 25, which has appreciable advantages to be presently described. The orifice 29 is constructed by drilling the passageway 28 with an extremely small drill completely through the end of the cap 26. The cap 26 is preferably formed with a conical point 30 concentric with respect to the passageway 28, and in the formation of the orifice 29, the apex of the said conical cap 26 is pounded flat or otherwise swedged to reduce the diameter of the passageway 28 so as to form the desired orifice.

Within the upper chamber 10 is disposed a float 31 which is mounted upon a vertically re ciprocable rod 32 by means of a set screw 33 or by any other desirable method. The rod 32 is of smaller diameter than the bore of the tube 12, and is slidably mounted in the upper portion of said tube and in a vertical hole 34 centrally drilled in the closure or cover 14. This construction serves as a guide for guiding the movement of the float and it can readily be comprehended that any other suitable means may be employed for guiding the same. As the chamber 35 formed within the receptacle 11 is brought under fluid pressure through the fluid within the pipe 23, mercury is forced up through the orifice 29 and the tube 12 into the receptacle 10 until a state of equilibrium is reached. The level of the mercury in this chamber varies with the pressure in the pipe 23 and rises and fails in accordance with the increase and decrease of pressure in said pipe. This causes the float 31 to be accordingly raised and lowered.

The upper end 36 of the rod 32 extends through an opening 37 in the bottom 38 of a case 39 in which the switch mechanism B is installed and into the interior thereof. This case may be of any suitable construction, the same merely serving to house the switch mechanism now to be described.

Within the interior of the case 39 is installed a frame 40 which is attached to the back 41 of said case through screws 42 and 43. This frame has rigidly attached to it a stud pin 44 which extends outwardly therefrom. Upon this pin is pivotally supported a mounting 45 which is provided with two cars 46 extending away from the same and preferably formed by bending the body of the said mounting. These ears are pivoted upon the stud pin 44 permitting of the oscillation of the mounting 45 in a manner to be presently described. The mounting 45 terminates in a lever 47 which is drilled, as indicated at 48, to encircle the upper end 37 of the rod 32. The hole 48 is of such a size as to not engage the rod 32 throughout the path of movement of the mounting 45. Attached to the mounting 45 are two U-shaped spring clips 49 and 50 which are secured thereto by means of rivets 51 and which are adapted to support a glass or other suitable tube 52 forming the switch proper of the inven tion. The tube 52 has imbedded in it two contacts 53 and 54 which are connected by means of flexible leads 55 and 56 with the particular circuit in which the switch is to be used. Within the tube 52 is a quantity of mercury 61. When the switch is in the position shown in Fig. 1, contacts 53 and 54 are imbedded in the said 110 mercury and electrically connected to close the circuit containing the leads 55 and 56.

The switch B is operated through the lever 47 by means of two collars 5'7 and 58 which are adjustably secured to the said rod by means of set 115 screws 59. As the rod 32 is raised and lowered through the float 31, the said collars 5'7 and 58 successively engage the arm 47 swinging the mounting 45 in a manner to open and close the switch.

For the purpose of causing the switch B to operate in a positive and effective manner, an off center device in the nature of an inverted pendulum is employed. This device comprises a rod 62 which is rigidly attached to the mounting 45 125 through a nut 63. At the end of the rod 72 is secured to it, by means of a set screw 64, a weight 65. The rod 62 is adapted to swing from an oif center position, as shown in Fig. 1, through dead center and to a similar off center position in the opposite direction. The movement of the said rod is limited by means of two stops 66 and 6'? which are attached to the upper portion of frame 40. If desired, resilient means may be employed instead of the weight 65.

For the purpose of preventing the switch from opening or closing while the pendulum is over dead center, the tube 52 is bent or curved intermediate its ends as indicated at 60. This prevents the mercury from flowing toward or from the contacts 53 and 54 when the weight is over dead center, as might readily occur with a straight tube.

In the operation of the device, upon the opening of the valve in pipe 23, the chamber 35 in receptacle 11 is brought under pressure. The fluid passing through the pipe 23 enters the T 18 where the same flows along the passageway between the said T and the tube 12 into the chamber 35. This forces the mercury within said r50 governed by the relative movement of the float chamber through the orifice 29,passageway 28 and tube 12 and into the receptacle 10 where the same rises to an elevation such as to counterbalance the fluid pressure of the system to which the device is connected. This causes the float 31 to raise and bring the collars 57 and 58 into proper position to swing the lever4'7 and actuate the switch proper. The switch B, as before stated, is connected to some'suitable circuit by means of which the fluid pressure within the reservoir is controlled. As the collar 57 engages the lever 4'7, the switch is thrown into closed position, causing the pressure in the reservoir to increase. As the pressure increases, the mercury within the receptacle 10 rises until the float 31 reaches an elevation suflicient to cause the collar 58 to swing the lever 47 sufficiently to throw the switch into open position. The means for controlling the fluid pressure is then disconnected and the device remains so disposed until the fluid pressure within the reservoir has been brought down to the minimum desirable pressure. 'The operation is then again repeated.

In the design of the system for use in conjunction with the control and indication of the pressure or head in water reservoirs, the procedure is as follows: The amount of force required to operate the switch B is first ascertained and a float 31 of suflicient weight and buoyancy to procure this force is then selected. The diameter of the receptacle 10 is then constructed of suflicient proportions to permit of the float 31 moving freely within the same. The height of the receptacle 10 is next determined by the variations in fluid pressure or head to be controlled. For ordinary water systems where a range of from 25 to 60 pounds of pressure is desired, a ratio of a quarter of an inch movement of the float 31 for every foot change in water level in the reservoir is found to be satisfactory. It must, however, be comprehended that any ratio may be had depending upon the particular application of the invention. The diameter of the receptacle 11 is next determined, which is 31 with respect to the corresponding movement of the water level of the reservoir. The length of the receptacle 11 is then designed so that the volume of the said receptacle is equal to the volume of the maximum displacement of the receptacle 10 or a little larger than the same so as to prevent the mercury from entering the pipe 23. The total height of the apparatus depends upon the relative heads of water in the Ireservoir, the said apparatus being designed to permit of the diiference of mercury level of one inch for every 1.131 feet of difference of level between the lower mercury level and the level of the water. In the installation of the device, the

icase 39 is attached to the wall of the building in which the device is to be installed through a number of screws 63, while the upper receptacle 10 is similarly attached to the wall in proper position through a cleat 69. It is to be noted that '1 the length of the entire device depends upon the elevation of the water in the reservoir or the fluid pressure in the system so that the higher the elevation of the device, the shorter the said device may be constructed. In the installation of the device, the length of the tube 12 is first determined and the proper length of tube inserted into the bushing 21. The said tube may be welded or otherwise secured to the said bushing or a suitable sliding joint interposed therein,

given a certain amount of adjustment of the distance apart of the receptacles 10 and 11 without effecting the-operation of the device.

When surges in the line connecting the fluid pressure operated device with the reservoir occur, the effect thereof upon the apparatus is dampened through the orifice 29. Due to the minuteness of this orifice, sufficient time is required for the necessary mercury to flow from the chamber'35, and into the receptacle 10, so that no appreciable movement of the float 31 occurs before the surge has disappeared. Only where the change in pressure occurs for the desired period of time will the elevation of the float 31 be varied and the corresponding operation of the switch B result. By the selection of the proper size of orifice, the degree of dampening can be regulated to meet with the requirements. 1

The invention is extremely simple and positive in action. By submerging the orifice of the device in the mercury, an extremely positive and effective dampening device is provided, due to the fact that all foreign substances, liquids or solids, which may be present in the receptacle 11 are considerably lighter than mercury and rise to the surface of the same. It is hence impossible to procure at the level of theoriflce 29 any such substances and clogging of this oriflce is hence entirely prevented. In the construction of the device, the cap 26 may be made of steel or of any other suitable material which will not amalgamate or be decomposed by the mercury. When the cap 26 has once been immersed, the same continues to function in the desired manner as long as the device is used. There are no wearing parts except the sliding joints for the float rod and the pivot for the switch mounting which may receive considerable wear without imparting the operation thereof. The device will practically operate continuously without attention or trouble. The device may be used for a number of. different purposes where fluid pressure or the head of the fluids within a reservoir or container is desired to be controlled or indicated. used in place of the switch B. A pointer may, if desired, be placed upon the rod 32 and used with a suitable scale for designating the actual height or fluid pressure in the reservoir whose pressure is to be controlled either in conjunction with or independent of the switch B. By properly setting the collars 5'7 and 58, the device can be made to operate within any limits of water heads desired and compensation can be made for line losses through the water distributing system and the conduit 23.

Changes in the specific form of my invention, as herein disclosed, may be made within the scope of what is claimed without departing from the spirit of my invention.

If desired, an indicating device may be i."

Ill

Having described my invention, what I claim as I new and desire to protect by Letters Patent is: 1. A pressure responsive device comprising connecting chambers containing a body of mercury, fluid pressure means associated with one is substantially circular cross section of pinhole size 1' submerged in the mercury, whereby flow of the mercury from one to the other of the chambers under changes in the fluid pressure is damped to a high degree.

2. A pressure responsive device comprising con- 5 necting chambers containing a body of mercury, fluid pressure means associated with one of the chambers and adapted to cause flow of mercury between the chambers under variations in fluid pressure, the connection between the chambers comprising a minute passageway having a fixed circular cross section submerged in the mercury adapted to highly damp the flow of mercury between the chambers and render the device nonresponsive to momentary fluctuations in fluid pressure.

3. A pressure responsive device comprising a mercury column adapted to be subjected to a variable fluid pressure at one end, an obstruction member provided with a restricted circular opening of fixed pinhole size submerged in the mercur y and restricting and highly damping the flow of mercury in said column in response to variations in the fluid pressure to which it is subjected, whereby the mercury column will be nonresponsive to momentary fluctuations in the fluid pressure.

4. In a fluid pressure responsive device, a tube having upper and lower portions, means for supporting a body of mercury with an exposed surface within said tube and another exposed surface outside of and above the lower portion of the tube, means for subjecting one of said exposed surfaces to a fluid pressure thereby to cause movement of mercury within the tube in response to variations in fluid pressure, and an obstruction member provided with a minute circular orifice of fixed pinhole size restricting such movement of mercury in the tube, whereby movements of the mercury in response to abrupt pressure fluctuations will be damped to a high degree.

5. A fluid pressure responsive device comprising connecting chambers containing a body of mercury, fluid pressure means associated with one of the chambers and adapted to cause flow of mercury between the chambers under variations in the fluid pressure, a member in the second chamber adapted to occupy different positions in said chamber in conformity with the quantity of mercury therein, electric circuit making and breaking means operated by said member, the connection between the mercury chambers comprising a restricted passageway having a substantially circular cross section of fixed pinhole size submerged on the mercury and adapted to highly damp and retard the flow of mercury between the respective chambers under variations in fluid pressure, whereby the member and the circuit making and breaking means operated thereby will not be afiected by momentary fluctuations in the fluid pressure.

IVAN G. RINGSTROM. 

